Server hangs after a while

Hi bukkit community.
I am new in mining and started with Client 1.2.3 - so I am not very experienced in this kind of server stuff When I start the server, sometimes it hangs while initializing, so i kill the processes and try again. It hangs on this state:

Code:

177 recipes
27 achievements
08:56:51 [INFORMATION] Starting minecraft server version 1.2.3
08:56:51 [INFORMATION] Loading properties
08:56:51 [INFORMATION] Starting Minecraft server on *:25565
08:56:51 [INFORMATION] This server is running CraftBukkit version git-Bukkit-1.2.3-R0.2-b2060jnks (MC: 1.2.3) (Implementing API version 1.2.3-R0.2)
>

When I have luck and the server comes up, it runs for a while and when I get back my screen session doesn't accept commands anymore. This happens with and without players on it.
The process ist still running and also uses the ram but has no cpu utilisation.

I installed craftbukkit on my vserver with following specs:

Code:

2.6.32-6-pve #1 SMP Fri Nov 4 06:54:05 CET 2011 i686 GNU/Linux (Debian wheezy testing)
java version "1.7.0"
Java(TM) SE Runtime Environment (build 1.7.0-b147)
Java HotSpot(TM) Client VM (build 21.0-b17, mixed mode)
total      used      free    shared    buffers    cached
5 Gigabyte ram

For now, I am using this version, but this problem also occured with 1.2.3-R0.1 (2034).

Code:

git-Bukkit-1.2.3-R0.2-b2060jnks (MC: 1.2.3) (Implementing API version 1.2.3-R0.2)

I am not using any wrappers.

Here is my starcommand:

Code:

java -Xmx2G -Xms2G -XX:+UseConcMarkSweepGC -XX:+CMSIncrementalPacing -XX:ParallelGCThreads=1 -XX:+AggressiveOpts -Djava.net.preferIPv4Stack=true -jar craftbukkit.jar nogui

I am using jCommands v1.0.2 but also tried to disable this - same problem.

Server.log doesn't show something useful:

Code:

2012-03-12 15:29:39 [INFO] Starting minecraft server version 1.2.3
2012-03-12 15:29:39 [INFO] Loading properties
2012-03-12 15:29:39 [INFO] Starting Minecraft server on *:25565
2012-03-12 15:29:40 [INFO] This server is running CraftBukkit version git-Bukkit-1.2.3-R0.2-b2060jnks (MC: 1.2.3) (Implementing API version 1.2.3-R0.2)
2012-03-12 15:30:05 [INFO] Starting minecraft server version 1.2.3
2012-03-12 15:30:05 [INFO] Loading properties
2012-03-12 15:30:05 [INFO] Starting Minecraft server on *:25565
2012-03-12 15:30:05 [INFO] This server is running CraftBukkit version git-Bukkit-1.2.3-R0.2-b2060jnks (MC: 1.2.3) (Implementing API version 1.2.3-R0.2)
2012-03-12 15:30:05 [INFO] [jCommands] Loading jCommands v1.0.2
2012-03-12 15:30:06 [INFO] Preparing level "cyberworld"
2012-03-12 15:30:06 [INFO] Default game type: 0
2012-03-12 15:30:06 [INFO] Preparing start region for level 0 (Seed: 2049430414069128955)
2012-03-12 15:30:07 [INFO] Preparing spawn area: 20%
2012-03-12 15:30:07 [INFO] Preparing start region for level 1 (Seed: 2049430414069128955)
2012-03-12 15:30:08 [INFO] Preparing spawn area: 32%
2012-03-12 15:30:09 [INFO] Preparing start region for level 2 (Seed: 2049430414069128955)
2012-03-12 15:30:09 [INFO] Preparing spawn area: 48%
2012-03-12 15:30:09 [INFO] [jCommands] Enabling jCommands v1.0.2
2012-03-12 15:30:09 [INFO] [jCommands] Initializing Commands.
2012-03-12 15:30:09 [INFO] [jCommands] jCommands v1.0.2 enabled.
2012-03-12 15:30:09 [INFO] Server permissions file permissions.yml is empty, ignoring it
2012-03-12 15:30:09 [INFO] Done (3,533s)! For help, type "help" or "?"

First I thought its a java problem so I tested folowing versions:

Code:

openJDK-6.jre
openJDK-7.jre
sun-java6.jre
latest sun-java7.jdk

 

I have just tested centos 6.2 on an openvz with suns Java(TM) SE Runtime Environment (build 1.7.0_03-b04) and its working without problems. I coppied my old craftbukkit dir to the new server to prevent all missconfigurations.
Strange strange :/

 

With openJDK6 64bit (IcedTea6 1.10.6) under CentOS 6.2 also no problems!